Introduce Invoke-CIPPRestMethod MVP and route core Graph helpers through it for low-risk REST migration

[Copilot]

• Review new PR comment and confirm whether it requires code changes or explanation
• Check workflow run status on dev and current branch per CI guidance
• Determine whether the reported variance indicates a regression in the current changes
• Reply to the PR comment with findings and next-step guidance
• Make code/test changes only if a concrete regression is identified

[Zacgoose]

@copilot would be we better off coupling this with a c# or similar compiled method instead of .net methods? No code changes yet just discuss

[Copilot]

@copilot would be we better off coupling this with a c# or similar compiled method instead of .net methods? No code changes yet just discuss

Short answer: not immediately. HttpClient is already compiled .NET, so switching from PowerShell cmdlet calls to C# only helps if we move the hot path (request construction + serialization + response parsing/retry) fully into a compiled cmdlet/library. The current wrapper gives us the right seam to do that later. I’d recommend profiling first, then only adding a C# helper if we see PowerShell overhead dominating after batching/retry/token optimizations. (current tip: b5621bf)

[Zacgoose]

@copilot
Graph Error: Could not get token: Response status code does not indicate success: 400 - Endpoint: users

http://localhost:4280/api/ListGraphRequest?tenantFilter=XXXXXXXXXXXX&Endpoint=users&manualPagination=true&$select=id,accountEnabled,businessPhones,city,createdDateTime,companyName,country,department,displayName,faxNumber,givenName,isResourceAccount,jobTitle,mail,mailNickname,mobilePhone,officeLocation,otherMails,postalCode,preferredDataLocation,preferredLanguage,proxyAddresses,showInAddressList,state,streetAddress,surname,usageLocation,userPrincipalName,userType,assignedLicenses,licenseAssignmentStates,onPremisesSyncEnabled,OnPremisesImmutableId,onPremisesLastSyncDateTime,onPremisesDistinguishedName&$count=true&$orderby=displayName&$top=999

[Copilot]

@copilot
Graph Error: Could not get token: Response status code does not indicate success: 400 - Endpoint: users

...

I tracked this to request-body encoding risk in the new HttpClient path and pushed a fix in 05e4891: dictionary/hashtable POST bodies are now sent as application/x-www-form-urlencoded (OAuth/token compatible) instead of JSON/string fallback. I also added coverage in Tests/GraphHelper/Invoke-CIPPRestMethod.Tests.ps1 and re-ran the GraphHelper Pester tests (pass). Please re-test that ListGraphRequest call on this branch.

[Zacgoose]

@copilot http://localhost:4280/api/ListUserPhoto?UserID=asdhasdasdfsdfdsfds - Exception calling ".ctor" with "3" argument(s): "The format of value 'application/json; charset=utf-8' is invalid."
WARNING: Exception occurred on HTTP trigger (Invoke-ListUserPhoto): Exception calling ".ctor" with "3" argument(s): "The format of value 'application/json; charset=utf-8' is invalid."

[Copilot]

@copilot http://localhost:4280/api/ListUserPhoto?UserID=asdhasdasdfsdfdsfds - Exception calling ".ctor" with "3" argument(s): "The format of value 'application/json; charset=utf-8' is invalid."
WARNI...

Fixed in 487aea5. Invoke-CIPPRestMethod now correctly handles content types like application/json; charset=utf-8 in HttpClient mode by constructing StringContent with the bare media type and then applying the full parsed Content-Type header. Added test coverage in Tests/GraphHelper/Invoke-CIPPRestMethod.Tests.ps1 and re-ran the GraphHelper Pester tests (pass).

[Zacgoose]

@copilot
it seems the .net method is a bit inconsistent:

cipp .net:
Total time: 238.1s
Requests: 1000 (1000 OK, 0 failed)
Avg duration: 7098ms
Min duration: 2620ms
Max duration: 16704ms
P50: 6240ms
P95: 12197ms
P99: 15365ms
Throughput: 4.2 req/s

Total time: 184.6s
Requests: 500 (500 OK, 0 failed)
Avg duration: 3346ms
Min duration: 2481ms
Max duration: 6143ms
P50: 2989ms
P95: 5094ms
P99: 5694ms
Throughput: 2.7 req/s

rest method:
Total time: 242.6s
Requests: 1000 (1000 OK, 0 failed)
Avg duration: 7192ms
Min duration: 2895ms
Max duration: 15726ms
P50: 6250ms
P95: 11747ms
P99: 12907ms
Throughput: 4.1 req/s

Total time: 189.5s
Requests: 500 (500 OK, 0 failed)
Avg duration: 3395ms
Min duration: 2649ms
Max duration: 7578ms
P50: 3001ms
P95: 4727ms
P99: 7511ms
Throughput: 2.6 req/s

[Copilot]

@copilot
it seems the .net method is a bit inconsistent:

...

These numbers look broadly in-family rather than a clear regression from the REST wrapper—P50/P95 and throughput are very close between both paths, with some run-to-run variance in tail latency. I haven’t made additional code changes from this report alone. If you want, I can add lightweight timing around request build/send/parse in Invoke-CIPPRestMethod behind a debug flag so we can pinpoint where tail jitter is coming from under load.